本文研究了由T-k-挠自由模所构成的mod-R的完全子模范畴I^bT(R)的扩张闭.利用模的级条件和强级条件,获得了I^bT(R)扩张闭的一个充分条件和一个等价刻画.
In this paper, we investigate extension closure of consisting of T-k-torsionfree modules by the grade condition and obtain a sufficent condition and an equivalence characterization for the full subcategory I^bT (R) of mod-R strong grade condition of modules, and I^bT (R) to be extension closed.